Methods and compositions for treating pulmonary disorders using optically pure (R,R) -formoterol

ABSTRACT

A method and composition are disclosed utilizing the pure (R,R) isomer of formoterol, which is a potent bronchodilator with reduced adverse effects, a low incidence of the development of tolerance and an increased duration of action, as compared to racemic formoterol.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of pending U.S. patentapplication Ser. No. 09/927,008, which was filed Aug. 9, 2001 as acontinuation of U.S. Ser. No. 09/535,200, which was filed Mar. 27, 2000as a continuation of U.S. Ser. No. 09/136,109 (now U.S. Pat. No.6,068,833), which was filed Aug. 18, 1998 as a continuation of U.S. Ser.No. 08/613,382 (now U.S. Pat. No. 5,795,564), which was filed Mar. 7,1996 as a continuation-in-part of U.S. Ser. No. 08/373,515 (nowabandoned), which was filed Jan. 12, 1995 as a continuation-in-part ofU.S. Ser. No. 08/222,319 (now abandoned), which was filed Apr. 4, 1994as a continuation of U.S. Ser. No. 07/927,458 (now abandoned), filedAug. 10, 1992.

[0002] U.S. Ser. No. 09/136,109 (now U.S. Pat. No. 6,068,833) was alsofiled as a continuation-in-part of U.S. Ser. No. 08/382,744 (nowabandoned), which was filed Feb. 2, 1995 as a continuation of U.S. Ser.No. 08/223,798 (now abandoned), which was filed Apr. 6, 1994 as acontinuation of U.S. Ser. No. 07/862,907 (now abandoned), which wasfiled Apr. 3, 1992 claiming priority under 35 USC 119, of Great Britainapplication 9107196.9, filed Apr. 5, 1991. The entire content of each ofthe prior applications is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0003] This invention relates to novel compositions of matter containingoptically pure (R, R)-formoterol. These compositions possess potent,long-lasting bronchodilating activity as β-adrenergic agonists whileavoiding or reducing adverse effects, including but not limited tomuscle tremor and tachycardia, as well as avoiding or reducing thedevelopment of tolerance or hypersensitivity on repeated administration.The compositions also provide an improved duration of action.

[0004] This invention also relates to methods of treating asthma,bronchitis, emphysema, bronchospasms, and other ailments in patientswith obstructive airway or allergic disorders, while avoiding adverseeffects, development of tolerance or hypersensitivity on repeatedadministration or a limited pattern of bronchial distribution whenadministered by inhalation.

[0005] The active compound of these compositions and methods is anoptical isomer of formoterol, which is described in Ida, “Arzneim,”Forsch., 26:839-842 and 1337-1340 (1976) and in U.S. Pat. No. 3,994,974.Chemically, the active compound isN-hydroxy-5-(1-hydroxy-2-[(2-(4-methoxyphenyl)methylethyl]amino]ethyl]phenylformamide,which exists as two enantiomeric pairs of diastereomers. Of these, theR,R diastereomer is the most active and, when substantially opticallypure, is hereinafter referred to as (R, R) formoterol. Formoterol isavailable commercially only as a racemic diastereomer: (R,R) and (S,S)in a 1:1 ratio, which is also the enantiomeric mixture referred to bythe generic name formoterol. The racemic mixture of (±) formoterol thatis commercially available for administration is a dihydrate of thefumarate salt.

[0006] When two chiral centers occur in the same molecule, each of themcan exist in two possible configurations, thus giving rise to fourcombinations: (R,R); (S, S); (R,S); and (S,R). The enantiomeric pair(R,R) and (S,S) are mirror images of each other and therefore sharechemical properties and melting points. Similarly, (R,S) and (S,R) arean enantiomeric pair. The mirror images of (R, R) and (S,S) are not,however, superimposable on (R,S) and (S,R). The relationship betweenthese two groups is called diastereomeric, and (R,R) is a diastereomerof (R,S). Due to its two chiral centers, formoterol falls into thiscategory.

[0007] Adrenergic or sympathomimetic drugs are so called because theyare understood to exert their effect through their action on the body'sadrenergic receptors of which there are three functionally dividedtypes: α, β₁ and β₂ receptors.

[0008] On the basis of their interaction with these three receptortypes, adrenergic or sympathomimetic drugs are in turn classified intothree groups:

[0009] 1.1 Non-selective sympathomimetic drugs;

[0010] 1.2 Non-selective β sympathomimetic drugs; and

[0011] 1.3 Selective β₂ sympathomimetic bronchodilator drugs.

[0012] Drugs of group 1.1 exert both α and β sympathomimetic effects.This class of drugs includes the substances adrenaline and ephedrine.Both adrenaline and ephedrine are known clinically as bronchodilators.Though adrenaline, despite side effects induced by its α-sympathomimeticproperties, is still used by some practitioners for the treatment ofacute asthma, both drugs have largely been replaced for asthma therapy.

[0013] The drugs of group 1.2 have both β₁ and β₂ sympathomimeticactivity but virtually no α-sympathomimetic activity. Of the group 1.2drugs, isoprenaline is the best known representative. Isoprenalinediffers from the drugs of group 1.3 in its faster onset but shorterduration of action and in its cardiac stimulating effects which resultlargely from its β₁ activity. Though isoprenaline was previouslyextensively used for bronchodilator therapy in asthma, its use today hasbecome clinically restricted. It is believed that a rise in the rate ofasthma deaths in the UK in the 1960's was associated with isoprenalineusage, and this has resulted in a discontinuation in its clinicalapplication.

[0014] The selective β₂ sympathomimetic bronchodilator drugs of group1.3 (hereinafter referred to collectively as “Group 1.3 drugs”) act, astheir name implies, selectively on β₂ adrenergic receptors. The Group1.3 drugs include for example, the drug substances terbutaline,albuterol, fenoterol, isoetharine, metaproterenol and, more recently,the so-called “long acting selective β₂ sympathomimetic bronchodilatordrug substances”—formoterol, bambuterol and salmeterol. All of the aboverecited Group 1.3 drugs are commercially available and clinically used,generally in a pharmaceutically acceptable salt form, such as, e.,g., asthe sulphate, hydrobromide, hydrochloride, fumarate or methanesulfonateor, where appropriate, one or other of the hydrate forms thereof.

[0015] Group 1.3 drugs characteristically contain as part of theirstructure an ethanolamine or a 2-aminoethanol moiety of formula I

[0016] wherein R1 is an aromatic group: commonly 3,4 or3,5-dihydroxyphenyl or 4-hydroxy-3-hydroxymethylphenyl, or, in the caseof formoterol, 3-formylamino-4-hydroxyphenyl.

[0017] R₂ and R₃ are commonly H.

[0018] Since the formula I moiety comprises at least 1 asymmetric carbonatom (C-1 in formula I), all of the Group 1.3 drugs exist in opticallyactive isomeric forms, with the chiral carbon atom having either the (R)or (S) configuration [as designated using the Cahn-Ingold-Prelog system(Angew, Chem. Intern. Ed. 5, 385-415(1966)]. When the C-1 carbon atom isthe sole asymmetric carbon atom present in the structure, Group 1.3drugs will exist as individual (R) or (S) enantiomers or in the racemic[(R,S)] form, i.e., as a 50:50 mixture of the (R) and (S) enantiomers.

[0019] Individual Group 1.3 drugs in which R₂ is other than H, or inwhich the remainder of the molecule includes an asymmetric carbon atom(formoterol, e.g.) exist in a variety of isomeric forms: (a) inindividual (R,R), (S,S), (R,S) and (S,R) isomeric forms; (b) as racemic(RS,RS) and (RS,SR) mixtures comprising the (R,R) with (S,S) and (R,S)with (S,R) enantiomeric pairs; as well as (c) in the form ofdiastereomeric mixtures comprising all four isomeric forms.

[0020] The Group 1.3 drugs can be administered orally, parenterally ormost commonly, by inhalation, e.g. using nebulizers or metered aerosoldevices or as inhaled powders. Inhalation of Group 1.3 drugs presentlyrepresents the mainstay of bronchodilator therapy for the treatment ofasthma of all grades of severity.

[0021] The duration of bronchodilation induced by the majority of Group1.3 drugs is relatively short and they are employed to relieve asthmaattack as and when it occurs. As indicated above, however, the morerecently introduced Group 1.3 drugs, such as formoterol, arecharacterized by their longer duration of action and hence an apparentreduced frequency of dosaging is required.

[0022] Although the Group 1.3 drugs are effective and generally seem tobe well tolerated, their safety, especially at high dosages, has beenquestioned over many years and numerous reports have appeared on theadverse effects of Group 1.3 drug therapy (see, e.g., Paterson et al.,American Review of Respiratory Disease, 120:844-1187 (1979), especiallyat page 1165 et seq.). More recently, from New Zealand, where acontinuing increase in asthma death has been recorded, two case controlstudies reported in The Lancet have linked an increase in asthmamortality to the use of the Group 1.3 drug, fenoterol; see, esp.,Editorial “β₂ agonists in asthma: relief, prevention, morbidity”,Lancet, 336:1411-1412 (1990).

[0023] A subsequently reported Canadian study found that the use ofinhaled Group 1.3 drugs, principally fenoterol and albuterol, isassociated with “an increased risk of the combined outcome of fatal andnear-fatal asthma, as well as of death from asthma alone.” Spitzer etal., New England J. Med., 326:501-506 (1992); and related Editorial,page 560.

[0024] Various possible explanations for observed episodes of increasedairway obstruction, arterial hypoxaemia or “anomalous” or “paradoxical”bronchospasm, as well as increased morbidity associated with Group 1.3drug usage, in particular long term/high dose usage, have been proposed.For example, reactive myogenic tone, increased inflammatory burden,adrenoceptor tachyphylaxis and induction of airway hyperreactivity, aswell as the involvement of spasmogenic drug metabolic products or longterm influence of aerosol spray propellants (see, e.g., Paterson et al.loc. cit. and Morley et al., Eur. Respir. J., 3:1-5 (1990).

[0025] There is mounting concern within the medical profession as to thepotential dangers of Group 1.3 drug usage in asthma therapy. To quotethe Lancet editorial already referred to:

[0026] “These studies raise serious question about the use of β₂agonists (i.e., Group 1.3 drugs). The findings of Sears et al. could beinterpreted as supporting the current trend towards earlier use ofcorticosteroids and other preventers of inflammation [for asthmatherapy] rather than perseverance with an escalating bronchodilatorregimen. The findings of the Nottingham and Dunedin groups also indicatethat there is some way to go before long acting β₂ agonist preparationssuch as salmeterol and formoterol can be unreservedly recommended forroutine use in the management of asthma. There seem to be clearadvantages of compliance and possibly of anti-inflammatory activityassociated with such agents, but the potential for adverse effectscannot be ignored. Clinicians, researchers and pharmaceutical companiesmust now attempt to redefine the use of β₂ agonists in asthma.”[Emphasis added.]

[0027] Equally, there has been an evident inability or reluctance toconceive of any problem in relation to Group 1.3 drug therapy as beinginherent in Group 1.3 drugs themselves or as hitherto employed: cf. thefollowing, taken from the previously cited editorial in the New EnglandJournal of Medicine.

[0028] “Although . . . too much reliance is placed on beta-agonists(Group 1.3 drugs], it is difficult to believe that the problem isrelated directly to the more regular use of inhaled beta-agonists.”

[0029] While the suitability, in particular of high dose or long-term,Group 1.3 drug therapy has long been a subject of debate, the practiceof administering drugs of this group as racemic mixtures has continued.This practice has been accepted by drug registration authoritiesworld-wide and even the most recently introduced of the Group 1.3 drugshave been developed for clinical use as racemic mixtures. This practiceis based upon the assumption or understanding that thenon-bronchodilator component of the racemic mixture, i.e., thebronchodilatorily-less or inactive enantiomer (distomer) is devoid ofany relevant drug effect and can thus be administered together with thebronchodilatorily-active isomer (eutomer) essentially as inactiveballast and without risk to the patient.

[0030] The teachings of the present invention thus stands in starkopposition to long, widely established and continuing practice, and runscontrary to the wisdom of the art.

[0031] As the Group 1.3 drugs clearly offer a very considerablepotential benefit for bronchodilator usage in asthma, the need to find ameans of avoiding, ameliorating or restricting any disadvantagesinherent in their use is urgent and crucial. By meeting this need, thepresent invention may be anticipated to bring immeasurable benefit bothto the medical profession, as well as to the population of asthmasufferers.

[0032] Formoterol, which is the subject of the present invention, iscurrently only available as a racemic mixture of the (R, R) and (S,S)diastereomers. Trofast et al., Chirality, 3:443-450 (1991) havedescribed the preparation of each of the substantially pure isomers, andthey have concluded that “[s]ince the (S,S) enantiomer is practicallyinactive, there is from this point of view no reason for its removalfrom the racemate in pharmaceutical preparations . . . ”.

[0033] Formoterol's primary use is as a long-acting bronchodilator forthe relief of reversible bronchospasm in patients with obstructiveairway disease such as asthma, bronchitis and emphysema.

[0034] Asthma, bronchitis and emphysema are known as Chronic ObstructivePulmonary Disease, or COPD. COPD is characterized as generalized airwaysobstruction, particularly of small airways, associated with varyingdegrees of symptoms of chronic bronchitis, asthma, and emphysema. Theterm COPD was introduced because these conditions often coexist, and itmay be difficult in an individual case to decide which is the majorcondition producing the obstruction.

[0035] Airways obstruction is defined as an increased resistance toairflow during forced expiration. It may result from narrowing orobliteration of airways secondary to intrinsic airways disease; fromexcessive collapse of airways during a forced expiration secondary topulmonary emphysema; from bronchospasm as in asthma; or may be due to acombination of these factors. Although obstruction of large airways mayoccur in all these disorders, particularly in asthma, patients withsevere COPD characteristically have major abnormalities in their smallairways, namely those less than 2 mm internal diameter, and much oftheir airways obstruction is situated in this zone. The airwaysobstruction is irreversible except for that which can be ascribed toasthma.

[0036] Asthma is a reversible obstructive lung disorder characterized byincreased responsiveness of the airways. Asthma can occur secondarily toa variety of stimuli. The underlying mechanisms are unknown, butinherited or acquired imbalance of adrenergic and cholinergic control ofairways diameter has been implicated. Persons manifesting such imbalancehave hyperactive bronchi and, even without symptoms, bronchoconstrictionmay be present. Overt asthma attacks may occur when such persons aresubjected to various stresses, such as viral respiratory infection,exercise, emotional upset, nonspecific factors, such as changes inbarometric pressure or temperature, inhalation of cold air or irritants,such as gasoline fumes, fresh paint and noxious odors, or cigarettesmoke, exposure to specific allergens, as well as the ingestion ofaspirin or sulfites in sensitive individuals. Psychologic factors mayalso aggravate an asthmatic attack but are not assigned a primaryetiologic role.

[0037] Persons whose asthma is precipitated by allergens (most commonlyairborne pollens and molds, house dust and animal dander) and whosesymptoms are IgE-mediated, are said to have allergic or “extrinsic”asthma. They account for about 10 to 20% of adult asthmatics; in another30 to 50%, symptomatic episodes seem to be triggered by non-allergenicfactors, such as, for example, infection, irritants and emotionalfactors, and these patients are said to have non-allergic or “intrinsic”asthma. In many persons, both allergenic and non-allergenic factors aresignificant. While allergies are said to be a more important factor inchildren than in adults, the evidence is inconclusive.

[0038] Chronic bronchitis (unqualified) is a condition associated withprolonged exposure to non-specified bronchial irritants and accompaniedby mucus hypersecretion and certain structural changes in the bronchi.Usually associated with cigarette smoking, it is characterizedclinically by chronic productive cough. The term chronic obstructivebronchitis is used when chronic bronchitis is associated with extensiveabnormalities of the small airways leading to clinically significantairways obstruction.

[0039] Pulmonary emphysema is enlargement of the air spaces distal toterminal non-respiratory bronchioles, accompanied by destructive changesof the alveolar walls. The term chronic obstructive emphysema is usedwhen airways obstruction is also present and where it is clear that themajor features of the disease can be explained by emphysematous changesin the lungs.

[0040] Many of the β₂ agonists cause somewhat similar adverse effects.These adverse effects include but are not limited to, the centralnervous system symptoms such as hand tremors, muscle tremors,nervousness, dizziness, headache and drowsiness; respiratory sideeffects such as dyspnea, wheezing, drying or irritation of theoropharynx, coughing, chest pain and chest discomfort; cardiovasculareffects such as palpitations, increased heart rate, and tachycardia.According to Trofast et al. (previously cited), (R,R) formoterol isprimarily a chronotropic agent in vitro with inotropic effects showingup at higher concentrations. The chronotropic effects are reported atconcentrations that are higher than those at which relaxation oftracheal muscle (bronchodilation) is seen. β₂ agonists (e.g.,dobutamine) are known in general to exhibit inotropic activity. Inaddition, racemic β₂ agonists can cause angina, vertigo, centralstimulation, insomnia, airway hyperreactivity (hypersensitivity),nausea, diarrhea, dry mouth and vomiting. As with other pharmaceuticals,β₂ agonists sometimes cause systemic adverse effects such as weakness,fatigue, flushed feeling, sweating, unusual taste, hoarseness, musclecramps and backaches.

[0041] Furthermore, patients have a tendency to develop a tolerance tothe bronchodilating effect of the racemic mixture of formoterol. This isrelated to desensitization, one of the most clinically significantphenomena involving the beta-adrenergic receptor. It has been observedthat patients in prolonged beta-agonist therapy have a tendency toincrease the dosage of drug they use. This occurs because afterprolonged administration, the beta receptor appears to becomedesensitized to the agonist, thus requiring larger doses of the compoundto effect an equivalent physiological response.

[0042] The problem of desensitization is especially significant in thetreatment of diseases involving bronchospasms, such as asthma. Thetreatment of asthma usually involves self-administration either orallyor by aerosol, of beta-adrenergic agonists such as the racemic(R,R)/(S,S) mixture of formoterol. These agonists mediatebronchodilation and promote easier breathing. Asthmatic patientsutilizing β₂ agonists for a prolonged time gradually increase theself-administered dose in order to get a sufficient amount ofbronchodilation and relief in breathing. As a result of this increaseddosage, the agonist concentration builds to a sufficient level so as toenter the peripheral circulation where it acts on the beta receptors ofthe heart and vasculature to cause cardiovascular stress and otheradverse effects.

[0043] Moreover, when administering the racemic mixture of formoterol byinhalation, due to the particle size and air flow distributioncharacteristics of the racemic mixture of formoterol, the distributionof the compound into the smaller bronchioles is limited, which resultsin a decreased effectiveness of the compound. It is therefore desirableto find a compound with the therapeutic characteristics of formoterolwhich would not have the above described disadvantages.

SUMMARY OF THE INVENTION

[0044] It has now been discovered that the (R, R) isomer of formoterolis an effective bronchodilator that does not have certain adverseeffects associated with the administration of the racemic mixture of (R,R)/(S, S) formoterol. The present invention includes administering to ahuman (R, R) formoterol to cause bronchodilation and to decrease theseadverse effects.

[0045] Furthermore, it has also been discovered that by administeringonly the (R,R) isomer of formoterol, there is decreased tolerance andhypersensitivity to the compound, relative to that seen when the racemicmixture of formoterol is administered. In addition, it has beendiscovered that by administering the (R,R) isomer of formoterol byinhalation, it is possible to obtain improved distribution of thecompound in the smaller bronchioles, resulting in an increasedbronchodilating effect. In addition, an increased duration of thebeneficial effects is observed upon administration of the substantiallypure (R,R) enantiomer, as compared to administration of the racemicdrug.

[0046] The present invention also includes novel compositions of mattercontaining optically pure (R,R) formoterol which is useful as abronchodilator. These novel compositions also avoid the above describedadverse effects, increased tolerance and limited pattern of distributionwhen administered by inhalation, effects associated with the racemicmixture of formoterol.

DETAILED DESCRIPTION OF THE INVENTION

[0047] The present invention encompasses a method of eliciting abronchodilator effect while avoiding the concomitant liability ofadverse effects, the development of tolerance, and a limited pattern ofbronchial distribution when administered by inhalation. The methodinvolves administering to a human in need of bronchodilation an amountof (R,R) formoterol or a pharmaceutically acceptable salt thereof,substantially free of its (S,S) stereoisomer, which is sufficient toalleviate bronchospasms, but insufficient to cause the described adverseeffects, development of tolerance, hypersensitivity or limited patternof bronchial distribution when administered by inhalation.

[0048] The bronchodilator effects are achieved by utilizing the highlypotent β-adrenergic effects of the (R,R) isomer of formoterol whilesubstantially limiting the adverse effects, development of tolerance,hypersensitivity or limited pattern of bronchial distribution whenadministered by inhalation, by decreasing or eliminating the amount of(S,S) isomer in the composition.

[0049] As hereinbefore described in relation to formula I, the C-1 inthe eutomer of Group 1.3 drugs characteristically has the (R)configuration. In the case of Group 1.3 drugs having two asymmetriccarbon atoms, the eutomer could therefore be the (R,R) or (R,S) isomer.Although we have found that the (R,R) enantiomer has the greatestbronchodilator potency, Group 1.3 drugs having two asymmetric carbonatoms have hitherto been used in the clinic generally in the form of the(RS,RS) racemic mixture.

[0050] The present invention also encompasses a bronchodilatorcomposition for the treatment of a patient in need of bronchodilatingtherapy which comprises an amount of (R,R) formoterol or apharmaceutically acceptable salt thereof, substantially free of its(S,S) stereoisomer, sufficient to alleviate bronchospasms butinsufficient to cause adverse effects, development of tolerance orlimited bronchial distribution when administered by inhalation.

[0051] The racemic mixture of formoterol causes bronchial smooth musclerelaxation and modulates inhibition of mediator release effect; however,this racemic mixture also causes adverse effects, leads to thedevelopment of tolerance and the development of hypersensitivity andresults in a limited pattern of bronchial distribution when administeredby inhalation. Utilizing the (R,R) isomer of formoterol results indiminished adverse effects, decreased development of tolerance andincreased bronchial distribution when the compound is administered byinhalation. Thus, it is much more desirable to use the (R,R) isomer offormoterol when treating asthma, bronchitis, emphysema or to alleviatebronchospasms.

[0052] Furthermore, although there is some variability from one patientto another, it is generally observed that, by administering an effectiveamount of only the (R,R) isomer of formoterol, it is possible toaccomplish a more “targeted” therapy. A more “targeted” therapy meansthat by using the (R,R) isomer, the compound's activity can be takenadvantage of without also having consequences of the pharmacologiceffects of the (S,S) isomer which are observed upon administration ofthe racemic mixture. This is important since it is not desirable for allpatients to be administered a compound with such a multifaceted spectrumof activity.

[0053] The present invention provides a method or use for the treatmentof inflammatory airways disease, in particular for effectingbronchodilatation, e.g., as a means of alleviating airways obstruction,in particular acute airways obstruction, e.g., asthma attack, occurringin such disease. The invention thus provides symptomatic, rather thanprophylactic, therapy for such disease.

[0054] The teaching of the present invention is applicable in thetherapy of inflammatory or obstructive airways disease, in particularany such disease for which Group 1.3 drug therapy is commonly practiced,for example chronic obstructive pulmonary disease, e.g., consequentialto cystic fibrosis, emphysema and, especially, chronic bronchitis and,most especially, asthma.

[0055] The present invention avoids deleterious side effectshereinbefore resulting or observed in, e.g., asthmatic, patientsconsequent to conventional clinical usage of Group 1.3 drugs as racemicmixtures. In particular, the invention provides means to avoid,ameliorate or restrict deleterious side effects, e.g., side effectsdeleterious to the airways. Thus the invention provides means to avoid,ameliorate or restrict exacerbation of disease status, for example basaldisease, e.g., basal asthmatic, status or to avoid, ameliorate orrestrict compromise or deterioration of lung function, or any other sideeffect concomitant to conventional clinical usage, for example“anomalous”, “rebound” or “paradoxical” bronchospasm and, especially,increase in airway obstruction, exacerbation of late asthmatic responseor non-specific bronchial reactivity or arterial hypoxemia.

[0056] Without limiting the present invention to any specific theory ormode of action, the present invention is in particular to be understoodas providing a means for the avoidance, amelioration or restriction ofexacerbation of airways hyperreactivity and/or of an inflammatory orother event associated with, or which is an etiological component of,inflammatory or obstructive airways disease, e.g., asthma. Such eventsare to be understood as including for example, inflammatory cellinfiltration of the lungs or airways, connective tissue deposition orsmooth muscle hyperplasia within the lungs or airways or othermorphological change associated with asthmatic status. The presentinvention also provides a means of preventing or reducing morbidity,e.g., asthma morbidity, ascribable to conventional, e.g., high dosage orlong term, Group 1.3 drug usage.

[0057] The present invention is especially applicable in the therapy ofbronchial asthma of whatever type or genesis. It is applicable to bothintrinsic and extrinsic asthma. It is especially applicable to thetreatment of allergic or atopic (i.e., IgE-mediated) asthma ornon-atopic asthma, as well as exercise induced asthma, occupationalasthma, asthma induced following bacterial infection or drug, e.g.aspirin, ingestion and other non-allergic asthmas.

[0058] Treatment of asthma is also to be understood as embracingtreatment of subjects of less than 4 or 5 years of age, exhibitingchronic cough or wheezing symptoms, in particular at night, anddiagnosed or diagnosable as “wheezy infants”, i.e., as embracing thetreatment of “wheezy infant syndrome”. Other diseases to which thepresent invention is in particular applicable include for example,chronic obstructive pulmonary or airways disease (COPD or CORD).

[0059] The term “adverse effects” includes but is not limited, to handtremors, muscle tremors, nervousness, palpitations, tachycardia,increased heart rate, dyspnea, coughing, chest pain, chest discomfort,drying or irritation of the oropharynx and wheezing. Also included inthe term “adverse effects” are headaches, dizziness, fatigue,hoarseness, backaches, nausea, vomiting, drowsiness, weakness, flushedfeeling, sweating, unusual taste, muscle cramps, weakness, angina,vertigo, central stimulation, hypersensitivity and insomnia.

[0060] The term “substantially free of the (S,S) stereoisomer” as usedherein means that the composition contains at least about 90% by weightof (R,R) formoterol and 10% or less by weight of (S,S) formoterol.

[0061] In a more preferred embodiment the composition contains at least99% by weight (R,R) formoterol and 1% or less of (S,S) formoterol. Inthe most preferred embodiment, the composition contains greater than 99%by weight of (R, R) formoterol and less than 1% by weight of (S,S)formoterol.

[0062] The term “eliciting a bronchodilator effect” means relief fromthe symptoms associated with obstructive airway diseases, which includebut are not limited to respiratory distress, wheezing, coughing,shortness of breath, tightness or pressure in the chest and the like.

[0063] The term “development of tolerance” means that when administeringthe racemic mixture of formoterol in repeated dosage or over a period oftime, the amount of the compound given to the patient must be increasedin order to achieve the same effect as the lower dosage given at anearlier time.

[0064] The term “limited pattern of bronchial distribution whenadministered by inhalation” means that therapeutically efficaciousquantities cannot penetrate into smaller bronchioles.

[0065] The mixture of formoterol isomers can be prepared according toU.S. Pat. No. 3,994,974. The diasteromers may be separated as describedby Murase et al., Chem. Pharm. Bull., 25:1368-13 (1977). The individualisomers of formoterol may be obtained as described by Trofast et al..,previously cited, by stereo controlled synthesis from optically activestarting material or by resolution of a mixture of enantiomers (i.e.,the racemic mixture) using conventional means, such as an opticallyactive resolving acid. Other standard methods of resolution known tothose skilled in the art including but not limited to simplecrystallization and chromatographic resolution can be used. See, e.g.,Eliel, E. L., Stereochemistry of Carbon Compounds, McGraw Hill 1962;Wilen, S. A. et al., “Tables of Resolving Agents,”, J. Chromatog.,113:283-302 (1975). Additionally, the optically pure (R,R) isomer can beprepared from the racemic mixture by enzymatic biocatalytic resolution,as described, for example, in U.S. Pat. Nos. 5,057,427 and 5,077,217,the entire disclosures of which are incorporated herein by reference.

[0066] The magnitude of a prophylactic or therapeutic dose of (R,R)formoterol in the acute or chronic management of disease will vary withthe severity of the condition to be treated, and the route ofadministration. The dose, and perhaps the dose frequency, will also varyaccording to the age, body weight, and response of the individualpatient. In general, the total daily dose ranges when administered byinhalation, for the conditions described herein, is from about 1 μg toabout 100 μg, in single or divided doses. Preferably, a daily dose rangeshould be between about 6 μg to about 25 μg, in single or divided doses,while most preferably, a daily dose range should be between about 12 μgto about 25 μg, in from two to four divided doses.

[0067] In managing the patient, the therapy should be initiated at alower dose, perhaps about 3 μg to about 12 μg, and increased up to about2×12 μg or higher depending on the patient's global response. Whenadministered orally, preferably as a tablet, the preferred dose range isfrom 0.1 to 1.0 mg per day. It is further recommended that children, andpatients over 65 years, and those with impaired renal, or hepaticfunction, initially receive low doses, and that they be titrated basedon individual responses and blood level(s). It may be necessary to usedosages outside these ranges in some cases as will be apparent to thoseskilled in the art. Further, it is noted that the clinician or treatingphysician would know how and when to interrupt, adjust, or terminatetherapy in conjunction with individual patient response.

[0068] The terms “an amount sufficient to alleviate bronchospasms butinsufficient to cause said adverse effects” are encompassed by theabove-described dosage amounts and dose frequency schedule.

[0069] Any suitable route of administration may be employed forproviding the patient with an effective dosage of (R,R) formoterol. Forexample, oral, rectal, parenteral (subcutaneous, intramuscular,intravenous), transdermal, and like forms of administration may beemployed. Dosage forms may include tablets, troches, dispersions,suspensions, solutions, capsules, patches, and the like.

[0070] The pharmaceutical compositions of the present invention comprise(R,R) formoterol as the active ingredient, or a pharmaceuticallyacceptable salt thereof, and may also contain a pharmaceuticallyacceptable carrier, and optionally, other therapeutic ingredients. Theterm “pharmaceutically acceptable salts” or “a pharmaceuticallyacceptable salt thereof” refer to salts prepared from pharmaceuticallyacceptable nontoxic acids including inorganic acids and organic acids.Suitable pharmaceutically acceptable acid addition salts for thecompound of the present invention include acetic, benzenesulfonic(besylate), benzoic, camphorsulfonic, citric, ethenesulfonic, fumaric,gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic,malefic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic,pantothenic, phosphoric, succinic, tartaric, p-toluenesulfonic, sulfuricand the like. The fumaric acid salt is particularly preferred.

[0071] The compositions of the present invention include compositionssuch as suspensions, solutions and elixirs; aerosols; or carriers suchas starches, sugars, microcrystalline cellulose, diluents, granulatingagents, lubricants, binders, disintegrating agents, and the like. Thecompositions include compositions suitable for oral, rectal, parenteral(including subcutaneous, transdermal, intramuscular, and intravenous)and inhalation, although the most suitable route in any given case willdepend on the condition being treated and the nature and severity ofthat condition.

[0072] The most preferred routes of the present invention are: (1) oralby either tablets or capsules; (2) inhalation; and (3) transdermal bypatch. They may be conveniently presented in unit dosage form andprepared by any of the methods well-known in the art of pharmacy.

[0073] In addition to the common dosage forms set out above, thecompounds of the present invention may also be administered bycontrolled release means and/or delivery devices such as those describedin U.S. Pat. Nos. 3,845,770; 3,916,899; 3,536,809; 3,598,123; and4,008,719, the entire disclosures of which are hereby incorporated byreference.

EXAMPLES

[0074] The invention is further defined by reference to the followingexamples describing in detail the pharmacological characterization ofthe compound, and the preparation of compositions of the presentinvention. It will be apparent to those skilled in the art, that manymodifications, both to materials, and methods, may be practiced withoutdeparting from the purpose and interest of this invention.

Procedure 1 β-Adrenergic Receptor Phosphorylation by β-AdrenoreceptorKinase

[0075] Reconstituted β-adrenergic receptor is incubated withβ-adrenoreceptor kinase in a buffer containing 20 mM Tris-HCl, pH 7.5, 2mM EDTA, 20 mM NaCl, 6 mM MgCl₂, 6 mM sodium phosphate, 0.5 mM ascorbicacid 60 μM [γ⁻³² P] ATP at 30° C. The incubations also contain varyingconcentrations of one of the following: (a) buffer (control); (b)(−)-isoproterenol; (c) R,R-formoterol; (d) S,S-formoterol; or (e)racemic formoterol. The incubations are stopped by the addition of SDSsample buffer followed by electrophoresis on 10% homogeneouspolyacrylamide gels.

[0076] Stoichiometries of phosphorylation are determined by cutting andcounting the dried gel as described in Benovic J. L. et al., J. Biol.Chem., 9026-9032 (1987).

Procedure 2 Purification of Component Proteins

[0077] The β-adrenergic receptor from hamster lung is purified to >9%homogeneity by sequential affinity chromatography and high performanceliquid chromatography as described by Benovic et al., Biochemistry,23:4510-4518 (1984). The stimulatory guanine nucleotide regulatoryprotein is purified from membranes derived from bovine cerebral cortex.The membranes, solubilized with 1% cholate, are centrifuged and theresulting supernatant chromatographed on DEAF-Sephacel, Ultrogel AcA34,octyl-Sepharose, and hydroxyapatite, with a final step on DEAE-Sephacel,as adapted from Strittmater and Neer, Proc. Natl. Acad. Sci.,77:6344-6348 (1980). The resulting protein should be 50-90% pure byCoomassie Blue staining of polyacrylamide gels.

[0078] The catalytic moiety of adenylate cyclase is solubilized frombovine caudate with sodium cholate and isolated from the othercomponents of the system by Sepharose 6B chromatography as described inStrittmater and Neer, Proc. Natl. Acad. Sci., 77:6344-6348 (1980).β-Adrenoreceptor kinase is purified from bovine cerebral cortex. Thetissue is homogenized, and the resulting high speed supernatant fractionis precipitated with 13-26% ammonium sulfate. This material is thenchromatographed on Ultrogel AcA34, DEAE-Sephacel, and CM-Fractogel. Thepreparations used should be 10-20% pure as judged by Coomassie Bluestaining of SDS-polyacrylamide gels.

Assay for Adenylate Cyclase Activity

[0079] The co-reconstitution of the purified proteins is carried out asdescribed in Cerione et al., J. Biol. Chem., 259:9979-9982 (1984). Thepelleted proteins are incubated for 15 min at 37° C. in 30 mM Tris-HCl,pH 7.5 containing 1 mM ATP, 2 μCi of [α⁻³²P] ATP, 0.14 mM cAMP, 100 mMsucrose, 0.4 mM dithiothreitol, 2.8 mM phosphoenol pyruvate, 5.2 μg/mLpyruvate kinase, 10 μg/ml of myokinase, 5 mM MgCl₂, and varyingconcentrations of racemic formoterol, (R,R) formoterol and (S,S)formoterol (total volume=0.5 mL). The reaction is stopped by theaddition of 0.25 mL 2% sodium dodecylsulfate containing 40 mM ATP and1.4 m.M cAMP at pH 7.5.

[0080] Water (0.5 mL) is added to each reaction tube and the contentsplaced on a Dowex 50AG WX4 resin. The eluate from the columns plus twosuccessive water washes (1.0 mL) are discarded. The columns are theneluted with 3 mL water and the eluates collected in test tubes. Eachfraction is diluted with 0.2 mL of 1.5 M imidazole HCl, pH 7.2. Thetubes from each concentration (run in triplicate) are combined anddecanted into columns 0.6 g neutral alumina that has been washed with0.1 M imidazole HCl, pH 7.5. The eluate is collected in scintillationvials containing 12 mL Aquasol®. After the columns are completelydrained, they are washed with an additional 1 mL of 0.1 M imidazole HCl,pH 7.5 which is collected in the same scintillation vials. Theconcentration of ³²P-cAMP is determined in each sample.

[0081] The metabolic rates of the racemate and the isomers of formoterolhave been studied in human It was unexpectedly found that the issignificantly slower for (R,R) formoterol than for the racemate and forthe (S,S) isomer. These new findings show that the clearance(V_(max)/K_(m)) was 152 for (R,R) formoterol, 381 for (S,S) formoteroland 489 for (R,R/S,S) formoterol. It is possible to calculate therelative biological half-lives (t_(1/2)) of the (R,R) isomer and theracemate from these data, using the formula C1=Vd×0.693/t_(1/2).Assuming the same distribution volume [Vd=1] for all three compounds,the relative half-lives are 4.6 for (R,R) formoterol and 1.4 for (R,R/S,S) formoterol.

[0082] Thus, the half-life of (R,R) formoterol is approximately threetimes longer than the half life of the racemate. This demonstrates asignificant advantage of the pure (R,R) enantiomer in terms of itsduration of action as well as a diminution of side effects.

Formulation Examples

[0083] Oral Tablet Formulations 12 mcg (R,R)- 25 mcg (R,R)- FORMOTEROLFORMOTEROL TABLETS TABLETS Ingredient Quantity per tablet (mg) Quantityper tablet (mg) (R,R)-Formoterol 0.12 0.25 Lactose 41.38 41.25Cornstarch 3.00 3.0 Water* 30.00 ml 30.0 ml Cornstarch 5.00 5.00Magnesium Stearate 0.50 0.50 50.00 50.00

[0084] The formoterol is blended with the lactose until a uniform blendis formed. The smaller quantity of cornstarch is blended with the waterto form the resulting cornstarch paste. This is then mixed with saiduniform blend until a uniform wet mass is formed. The remainingcornstarch is added to the resulting wet mass and mixed until uniformgranules are obtained. The granules are then screened through a suitablemilling machine, using a ¼ inch stainless steel screen. The milledgranules are then dried in a suitable drying oven until the desiredmoisture content is obtained. The dried granules are then milled througha suitable milling machine, using ¼ mesh stainless steel screen. Themagnesium stearate is then blended and the resulting mixture iscompressed into tablets of desired shape, thickness, hardness anddisintegration. Oral Inhalation Formulation 7.5 mL (10.5 g) Metered DoseCanister Quantity per Ingredient Canister (R,R)-Formoterol 1.8 mgTrichloromonofluoromethane 5.16 g Dichlorodifluoromethane 5.16 gSorbitan trioleate 0.105 g

[0085] The metered dose dispenser contains micronized (R, R) formoterolfumarate dehydrate in suspension. Each actuation delivers 6 Ag of (R,R)formoterol fumarate dehydrate from the mouthpiece. Each canisterprovides about 300 inhalations.

We claim:
 1. A method for treating chronic obstructive pulmonary diseasein a human in need of such therapy, the method comprising administeringto the human a therapeutically effective amount of (R,R)-formoterol, ora pharmaceutically acceptable salt thereof, the (R,R)-formoterolcontaining at least 90% by weight of (R,R)-formoterol and less than 10%by weight of (S,S)-formoterol.
 2. The method of claim 1, wherein the(R,R)-formoterol is administered by subcutaneous injection, intravenousinfusion, inhalation, transdermal delivery or oral administration. 3.The method of claim 2, wherein the (R,R)-formoterol or pharmaceuticallyacceptable salt thereof is administered together with a pharmaceuticallyacceptable carrier.
 4. The method of claim 2, wherein the(R,R)-formoterol is administered as the fumarate dehydrate salt.
 5. Themethod of claim 2, wherein the (R,R)-formoterol is administered byinhalation and the amount administered is about 1 μg to about 100 μg perday, in single or divided doses.
 6. The method of claim 5, wherein theamount administered is about 6 μg to about 25 μg per day, in single ordivided doses.
 7. The method of claim 6, wherein the amount administeredis about 12 μg to about 25 μg per day, in single or divided doses. 8.The method of claim 7, wherein the amount is administered in from two tofour divided doses.
 9. The method of claim 2, wherein the(R,R)-formoterol is administered by orally and the amount administeredis about 0.1 mg to about 1 mg per day.
 10. A method for treating chronicobstructive pulmonary disease in a human in need of such therapy, themethod comprising administering to the human a therapeutically effectiveamount of (R,R)-formoterol, or a pharmaceutically acceptable saltthereof, the (R,R)-formoterol containing at least 90% by weight of(R,R)-formoterol and less than 10% by weight of (S, S)-formoterol, andwherein the amount of (R,R)-formoterol is sufficient to treat COPD, butinsufficient to cause adverse effects associated with racemicformoterol.
 11. The method of claim 10, wherein the (R,R)-formoterol isadministered by subcutaneous injection, intravenous infusion,inhalation, transdermal delivery or oral administration.
 12. The methodof claim 11, wherein the (R,R)-formoterol or pharmaceutically acceptablesalt thereof is administered together with a pharmaceutically acceptablecarrier.
 13. The method of claim 11, wherein the (R,R)-formoterol isadministered as the fumarate dehydrate salt.
 14. The method of claim 11,wherein the (R,R)-formoterol is administered by inhalation and theamount administered is about 1 μg to about 100 μg per day, in single ordivided doses.
 15. The method of claim 14, wherein the amountadministered is about 6 μg to about 25 μg per day, in single or divideddoses.
 16. The method of claim 15, wherein the amount administered isabout 12 μg to about 25 μg per day, in single or divided doses.
 17. Themethod of claim 16, wherein the amount is administered in from two tofour divided doses.
 18. The method of claim 11, wherein the(R,R)-formoterol is administered by orally and the amount administeredis about 0.1 mg to about 1 mg per day.